Hypoglycemia remains a major limiting factor toward the intensification of treatment for diabetes mellitus 1 and is a major cost to patients and to health care systems. 2 Hypoglycemia is often divided into mild or nonsevere hypoglycemia episodes (NSHE), where the person is able to selftreat, and severe hypoglycemia (SH), where external assistance is required. It is difficult to set a biochemical threshold for hypoglycemia, as the glucose threshold at which symptoms of hypoglycemia can be detected vary between individuals and even from day to day within the same person.3 The ADA workgroup on hypoglycemia offers some consensus guidelines, defining an alert value of ≤70 mg/dl, measured through self-monitored blood glucose (SMBG) or subcutaneous continuous glucose monitoring (CGM), as indicative of the potential for developing hypoglycemia. 4 All those treated with insulin secretagogues (sulphonylureas, glinides) and insulin therapy are at risk of hypoglycemia, and this risk is increased in the presence of endogenous insulin deficiency, longer duration of diabetes and longer duration of insulin therapy.5 Epidemiological data suggest that people with type 1 diabetes (T1D) with optimal glycemic control experience up to 2 mild episodes/week, with 20-30% experiencing episodes severe enough to require external help in any given year.6 A small proportion of these people, usually with impaired awareness of hypoglycemia, contribute to more than half of the incidence of SH, having recurrent disabling and sometimes life threatening events.
7CGM studies designed to study normative data suggest that while hypoglycemia is common in all insulin-treated people with diabetes, compared to subjects with type 2 diabetes (T2D), T1D subjects had twice as many hypoglycemic episodes per day, with more hours per day in the hypoglycemic range.8 However, although the incidence per patient of NSHE and SH is lower in T2D, due to the greater prevalence of T2D, the majority of episodes of SH occur in people with T2D. 9 In the US, rates of admissions for hypoglycemia have increased in recent years to 105 admissions per 100 000 person-years. 10 Antecedent hypoglycemia has been shown to blunt symptom and counter-regulatory hormonal responses to subsequent hypoglycemia.11 Over time, recurrent hypoglycemia eventually leads to a reduction in the ability to detect hypoglycemia and mount a hormonal response to it, known as impaired awareness of hypoglycemia (IAH) which can increase the risk of SH 6-fold. 12 In the T1D Exchange clinic registry, ≥ 1 SH events occurred in ~6% of over 9000 participants within 12 months, and was not associated with baseline glycated hemoglobin (HbA1c) levels. 13 Undoubtedly, SH has substantial clinical consequences on morbidity (both physical and psychological) and mortality. The more subtle effects of SH and hypoglycemia unawareness are often
AbstractHypoglycemia is a major barrier toward achieving glycemic targets and is associated with significant morbidity (both psychological and physical) and mortality. This article re...